diff options
| -rw-r--r-- | sys/vm/vm_pageout.c | 33 |
1 files changed, 9 insertions, 24 deletions
diff --git a/sys/vm/vm_pageout.c b/sys/vm/vm_pageout.c index 472ae78..5660b56 100644 --- a/sys/vm/vm_pageout.c +++ b/sys/vm/vm_pageout.c @@ -1333,25 +1333,6 @@ relock_queues: m = next; continue; } - object = m->object; - if (!VM_OBJECT_TRYWLOCK(object) && - !vm_pageout_fallback_object_lock(m, &next)) { - VM_OBJECT_WUNLOCK(object); - vm_page_unlock(m); - m = next; - continue; - } - - /* - * Don't deactivate pages that are busy. - */ - if (vm_page_busied(m) || m->hold_count != 0) { - vm_page_unlock(m); - VM_OBJECT_WUNLOCK(object); - vm_page_requeue_locked(m); - m = next; - continue; - } /* * The count for pagedaemon pages is done after checking the @@ -1367,7 +1348,15 @@ relock_queues: vm_page_aflag_clear(m, PGA_REFERENCED); act_delta += 1; } - if (object->ref_count != 0) + /* + * Unlocked object ref count check. Two races are possible. + * 1) The ref was transitioning to zero and we saw non-zero, + * the pmap bits will be checked unnecessarily. + * 2) The ref was transitioning to one and we saw zero. + * The page lock prevents a new reference to this page so + * we need not check the reference bits. + */ + if (m->object->ref_count != 0) act_delta += pmap_ts_referenced(m); /* @@ -1387,9 +1376,6 @@ relock_queues: * queue depending on usage. */ if (act_delta == 0) { - KASSERT(object->ref_count != 0 || - !pmap_page_is_mapped(m), - ("vm_pageout_scan: page %p is mapped", m)); /* Dequeue to avoid later lock recursion. */ vm_page_dequeue_locked(m); vm_page_deactivate(m); @@ -1397,7 +1383,6 @@ relock_queues: } else vm_page_requeue_locked(m); vm_page_unlock(m); - VM_OBJECT_WUNLOCK(object); m = next; } vm_pagequeue_unlock(pq); |
